Building panel having locking flange and locking receptacle
FIELD OF THE INVENTION 
     The present invention relates to a building panel for residential buildings and similar structures. More particularly, the invention relates to a vinyl soffit panel having an improved means for interlocking engagement with adjacent similar panels. 
     BACKGROUND OF THE INVENTION 
     Vinyl soffit units are known in the prior art. However, the prior art soffit units are generally difficult to manufacture and assemble, and they sometimes also have less than optimal strength and appearance. 
     Knoebl U.S. Pat. No. 4,461,128 issued July 24, 1984 discloses vinyl soffit configured for interlock with adjacent units and with supporting J-shaped or F-shaped channels. The Knoebl soffit panels appear to be made by a profile extrusion process whereas the building panels claimed herein are manufactured by a post forming extrusion process. 
     Some other references disclosing vinyl or metal building units adapted for interlock with adjacent units are Trachtenberg U.S. Pat. No. 3,325,952; Godes U.S. Pat. No. 3,473,274; Fritz U.S. Pat. No. 4,189,885; and Katz U.S. Pat. No. 4,450,665. Such references do not disclose or suggest a vinyl soffit panel having an integrally formed locking flange and locking receptacle as claimed herein. 
     A principal object of the present invention is to provide a building panel made from a synthetic polymer and having a locking flange and a locking receptacle configured for interlocking engagement. A related objective of the invention is to provide a building panel that is easy to manufacture and to assemble. 
     A further objective of the invention is to provide a building panel of the type described having high strength and a pleasant appearance. 
     Additional objectives and advantages of the invention will become apparent to persons skilled in the art from the following detailed description. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention there is provided a building panel made from a synthetic polymer and configured for interlocking engagement with adjacent similar panels. The building panel preferably comprises vinyl soffit but may also be used for other purposes such as siding material. 
     The building panel of the invention comprises a principal portion, a locking flange, and a locking receptacle adapted to interlock with a locking flange on an adjacent unit. 
     The principal portion has front and rear surfaces and spaced first and second lateral end portions. The front surface is generally flat, but may be interrupted by one or more indented, longitudinally extending ribs for added strength. The principal portion may also have vent openings, when desired to prevent undue accumulation of attic moisture. 
     The locking flange extends from the first lateral end portion of the principal portion. The flange comprises a leg extending rearwardly of the principal portion, a locking tab extending laterally outward of the leg behind the principal panel and a locking lug extending frontward from the locking tab. The locking flange is preferably generally L-shaped in cross-section. 
     The locking receptacle is attached to the second lateral end portion of the principal portion. The locking receptacle comprises an arm extending rearwardly from the principal portion, a flap attached to the arm, and a fastening strip extending laterally outward from the flap. The arm is preferably generally J-shaped in cross-section, comprising a connecting piece attached to the second lateral end portion and a curved elbow attached to the connecting piece. The flap is preferably C-shaped in cross-section. The flap and the arm define a locking notch for receiving a locking lug from an adjacent building panel. The locking tab enters the locking receptacle through a narrow passageway between the elbow and flap. 
     A fastening strip extends laterally outward from the flap. The fastening strip defines a plurality of fastening slots or nailing slots. The soffit panel is fixed in place by driving nails through these slots into wood studs at the construction site. 
     The vinyl soffit panel of the invention is manufactured by post forming extrusion. In this process, molten polymer material is extruded into a continuous sheet which is then punched to form fastening slots in the fastening strip and locking lugs in the locking tab. If desired, vent openings may also be provided in the principal portion. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of a preferred building panel made in accordance with the present invention. 
     FIG. 2 is a side elevational view of the building panel of FIG. 1. 
     FIG. 3 is an enlarged, fragmentary cross-sectional view of two interlocked building panels made in accordance with the invention. 
     FIG. 4 is a front elevational view of an alternative building panel made in accordance with the invention. 
     FIG. 5 is a cross-sectional view taken along the lines V--V of FIG. 4. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     A particularly preferred building panel or building unit 10 made in accordance with the present invention is shown in FIGS. 1 and 2. The building panel 10 principally comprises polyvinyl chloride and is intended for use as soffit in residential housing. 
     The soffit panel 10 comprises a principal portion 11 having a front surface or bottom surface 12 and rear surface or top surface 13. The portion 11 extends between a first lateral end portion 14 and a second lateral end portion 15. The portion 11 is preferably divided by a longitudinally extending, rearwardly depressed integral rib 17 approximately midway between the two lateral end portions 14, 15. The rib 17 adds rigidity to the portion 11. 
     A locking flange 20 extends from the first lateral end portion 14. The locking flange 20 includes a rearwardly or upwardly extending leg 21; a locking tab 22 extending laterally outward from the leg 21 behind the principal portion 11; and a locking lug 23 extending frontward or downward from the locking tab 22. As shown in FIG. 3, the locking flange 20 is generally L-shaped in cross-section. 
     The locking lug 23 is formed by displacing a portion of the tab 22 forwardly, so that an outer end 23a (FIG. 1) remains attached to the tab 22 and an inner end 23b (FIG. 1) is spaced frontward or downward from the tab 22. The tab 22 is formed with four small locking lugs 23 each spaced apart by a distance of a few inches as shown in FIG. 1. 
     A locking receptacle 30 extends from the second lateral end portion 15. The locking receptacle 30 has a complex shape comprising an arm 31 attached directly to the principal portion 11; a flap 40 attached to the arm 31; and a fastening strip or nailing strip 50 attached to the flap 40. The fastening strip 50 defines several spaced fastening slots or nailing slots 51. 
     The arm 31 comprises a connecting piece 33 attached to the second lateral end portion 15 and extending rearwardly. A curved elbow 35 is attached to the connecting piece 33. As shown in FIG. 3, the elbow comprises a first portion 36 extending laterally inward of the end portion 15 and a second portion 37 extending frontward of the first portion 36. 
     The flap 40 is attached to the elbow 35. The flap 40 is generally C-shaped in cross-section as shown in FIG. 3. The flap 40 comprises a laterally inwardly extending leg 40a; a rearwardly extending connector 40b; and a wing 40c attached to the connector 40b and extending laterally outwardly thereof. The wing 40c overlaps the arm 31. The flap 40 and arm 31 combine to define a locking notch 42 for receiving a locking lug 23 from an adjacent building unit. Entry to the locking notch 42 is obtained through a narrow passageway 44 between the elbow first portion 36 and wing 40c. 
     Referring to FIGS. 1 and 3, a fastening strip or nailing strip 50 extends laterally outward from the wing 40c. The fastening strip 50 defines several rectangular fastening slots or nailing slots 51. The soffit panel 10 is fixed to a building by driving nails through these slots 51 and into wood studs (not shown). 
     In FIG. 3, there is shown a joint 60 between two adjacent building panels of the present invention. When joined together as shown, the locking lugs 23 of one panel are firmly engaged in a locking notch 42 in the adjacent panel. Sizes of the passageway 44 and lug 23 are carefully controlled to prevent inadvertent detachment of the locking tab 22 from the locking notch 42. 
     An alternative embodiment of the building unit 10 is illustrated in FIGS. 4 and 5. In this embodiment, several vent openings 70 are formed in the principal panel 11. Such openings 70 are manufactured by die punching several small parts 71 of the principal panel 11 rearwardly so that such parts 71 remain only partially attached to the panel 11. The vent openings 70 provide sufficient ventilation to prevent excessive accumulation of attic moisture in moist climates. 
     The foregoing description of my invention has been made with reference to two preferred embodiments. Persons skilled in the art will understand that numerous changes and modifications can be made therein without departing from the spirit and scope of the following claims.